class Animal:
    def __init__(self,species,sound):
      if species in ['猫','狗','羊','猴子','老虎','大象']:
          self.species = species
          self.sound = sound
      else:
          self.species = None
          self.sound = None
    def speak(self):
        if self.species == None:
            print('动物园里没有动物，游戏结束！')
            return False
        else:
            print(self.species,self.sound)
            return True
print('动物园里有什么？')
flag = True
while flag:
    s = input('请输入动物种类和叫声(使用空格隔开）:')
    list1 = s.split(' ')
    animal = Animal(list1[0], list1[1])
    flag = animal.speak()